GLX: Numerical perturbations while moving hierarchies of pinned windows across desktops

[JulNadeauCA]

Hierarchies of pinned windows are used notably by dropdown and popup menus. AG_Menu creates sub-windows corresponding to the sub-items of a menu.

AG_DriverGLX relies on X Windows' ConfigureNotify in order to move pinned windows in response to their parent window being moved.

However, the reporting is not 100% accurate especially when moving across desktops, and this becomes more obvious with deeper levels of pinning. The deeper the menus, the more hilarious.

[JulNadeauCA]

Maybe this is related to OpenGL context creation? If so then perhaps that could be solved by having the AG_MenuView create its windows under an alternate (non-GL) driver.